Suggested by a Philips documentation from 1970, this circuit uses period components, operating at 50 Hz. The current consumed is 10 A and the input voltage is 12 V.
This different configuration for a crystal galena radio or modernized since a diode is used, has a...
This circuit is from 1990 documentation. When we press D1 the lamp remains on for a time interval that...
This version of the test lights a lamp when the ring touches the tortuous wire. The SCR can be the...